1. Field of the Invention
The invention relates to an illuminating apparatus for a liquid crystal projection display, more particularly to an illuminating apparatus that utilizes a plurality of light sources to generate input light for a projection display.
2. Description of the Related Art
In a conventional liquid crystal projection display, input light is separated into color components that are modulated and subsequently recombined to generate an image output. A single light source is commonly used to generate the input light in the conventional projection display. For projection displays with a high requirement of brightness, the single light source will incur a corresponding increase in power requirement. High-power single light sources are disadvantageous in that there is a severe heat dissipation problem that is difficult to resolve when such light sources are in use.
The object of the present invention is to provide an illuminating apparatus that utilizes a plurality of light sources to generate bright input light for a projection display.
According to the present invention, an illuminating apparatus comprises:
a lighting unit including a plurality of lighting members that are spaced apart from each other and that are operable so as to produce forwardly directed parallel light rays;
a first reflector disposed in front of the lighting unit and having a central region formed with an opening, and a peripheral region around the central region and formed with a first reflecting surface that confronts the lighting unit and that reflects the forwardly directed parallel light rays from the lighting members to converge rearwardly;
a second reflector disposed behind the first reflector and registered with the central region of the first reflector, the second reflector being formed with a second reflecting surface that faces the opening in the first reflector such that the light rays reflected from the first reflecting surface are further reflected by the second reflecting surface so as to pass through the opening in the first reflector; and
an integrator disposed in front of the first reflector and having an incident end disposed proximate to the opening in the first reflector to receive the light rays that pass through the opening, and a radiating end disposed opposite to the incident end.